Mob Farm

-- fuels up the turtle as much as it can
function fuelUp()
    print("Current Fuel Level: ",   turtle.getFuelLevel())
    if turtle.getFuelLevel() == turtle.getFuelLimit() then
        return
    end

    for i = 1, 16 do
        turtle.select(i)
        turtle.refuel(turtle.getItemCount(i))
        if turtle.getFuelLevel() == turtle.getFuelLimit() then
            break
        end
    end
    print("Current Fuel Level: ",   turtle.getFuelLevel())
end

-- checks if the turtle can hold more fuel
function checkFuel()
    if turtle.getFuelLevel() <= 0 then
        fuelUp()
    end
end

--[[14 - full block
    15 - slab
    16 - water bucket]]
function findBlock(block)
    for i = 1, 13 do
        turtle.select(i)
        if turtle.compareTo(block) then
            return i
        end
    end
    print("no more blocks, need a fillup")
end

--checks if there are any more blocks left in the stack, if not the find a new stack
function checkRemaining(block)
    if turtle.getItemCount() > 0 then
        return
    end
    findBlock(block)
end

--move the turtle forward a distance of dist
function forward(dist)
    for i = 1, dist do
        turtle.forward()
        checkFuel()
    end
end

--move the turtle forward a distance of dist placeing a block below it after each move
function placeForward(dist, block)
    for i = 1, dist do
        turtle.forward()
        turtle.placeDown()
        checkFuel()
        checkRemaining(block)
    end
end

function perimeter()
    findBlock(14)
    for i = 1, 4 do
        placeForward(19, 14)
        turtle.turnRight()
    end
end

--layer 1 functions

function funnels()
    --get to first block
    turtle.forward()
    turtle.turnRight()
    forward(8)
    turtle.turnLeft()

    --build the funnels
    findBlock(14)
    for i = 1, 4 do
        turtle.placeDown()
        for j = 1, 2 do
   findBlock(14)
            placeForward(7, 14)
            turtle.turnLeft()
        end
  turtle.turnRight()
  turtle.turnRight()
        for j = 1, 2 do
            turtle.forward()
            findBlock(16)
            turtle.placeDown()
        end
        turtle.forward()
        turtle.turnRight()
  findBlock(14)
  turtle.placeDown()
    end

    --get back to the initial location
    turtle.turnLeft()
    forward(8)
    turtle.turnLeft()
    turtle.forward()
    turtle.turnLeft()
    turtle.turnLeft()
end

--layer 2 functions

function placeSquare(num)
    checkRemaining(14)
    for i = 1, 8 do
        for j = 1, 8 do
            turtle.placeDown()
            checkFuel()
            checkRemaining(14)
            turtle.forward()
        end
        if i%2 == num then
            turtle.turnLeft()
            turtle.forward()
            turtle.turnLeft()
        else
            turtle.turnRight()
            turtle.forward()
            turtle.turnRight()
        end
  turtle.forward()
    end
end

function layer2()
    --get inside the wall
    turtle.forward()
    turtle.turnRight()
    turtle.forward()
    placeSquare(1)

    turtle.turnLeft()
    turtle.forward()
    turtle.forward()
    placeSquare(0)

    turtle.turnRight()
    turtle.forward()
    turtle.forward()
    placeSquare(1)

    turtle.turnRight()
    for i = 1, 11 do
        turtle.forward()
    end
    placeSquare(1)

    --return to start
    for i = 1, 9 do
        turtle.forward()
    end
    turtle.turnRight()
    for i = 1, 19 do
        turtle.forward()
    end
    turtle.turnRight()
 turtle.forward()
end

--layer 3 functions

function placeSlabs(turn)
    --row 1
    findBlock(15)
    for x = 1, 3 do
        turtle.placeDown()
        checkFuel()
        checkRemaining(15)
        forward(3)
    end

    --move to next row
    if turn == 0 then
        turtle.turnRight()
        forward(3)
        turtle.turnRight()
    else
        turtle.turnLeft()
        forward(3)
        turtle.turnLeft()
    end

    --row 2
    for i = 1, 3 do
        forward(3)
        turtle.placeDown()
        checkFuel()
        checkRemaining(15)
    end

    --move to next row
    if turn == 0 then
        turtle.turnLeft()
        forward(3)
        turtle.turnLeft()
    else
        turtle.turnRight()
        forward(3)
        turtle.turnRight()
    end

    --row 3
    for x = 1, 3 do
        turtle.placeDown()
        checkFuel()
        checkRemaining(15)
        forward(3)
    end
end

function slabs()

    --get inside the wall
    turtle.forward()
    turtle.turnRight()
    turtle.forward()
    turtle.turnLeft()

    placeSlabs(0)

    turtle.turnRight()
    forward(5)
    turtle.turnRight()
    forward(3)

    placeSlabs(1)
    turtle.turnRight()
    turtle.turnRight()

    forward(14)
    turtle.turnLeft()

    placeSlabs(0)

    turtle.turnLeft()
    forward(6)
    turtle.turnRight()
    forward(2)

    placeSlabs(0)

    --return to start
    turtle.turnLeft()
    forward(18)
    turtle.turnRight()
    turtle.forward()
    turtle.turnLeft()
    turtle.forward()
    turtle.turnLeft()
    turtle.turnLeft()
end

--layer 4 functions
function roof()
    checkRemaining(14)
    for i = 1, 19 do
        for j = 1, 19 do
            turtle.placeDown()
            checkFuel()
            checkRemaining(14)
            turtle.forward()
        end
        if i%2 == 0 then
            turtle.turnLeft()
            turtle.forward()
            turtle.turnLeft()
        else
            turtle.turnRight()
            turtle.forward()
            turtle.turnRight()
        end
    end

    --return to start
    for i = 1, 19 do
        turtle.forward()
    end
    turtle.turnRight()
    for i = 1, 19 do
        turtle.forward()
    end
    turtle.turnRight()
end

-- main function
function run()
    --1st layer of blocks
--  turtle.up()
--  perimeter()
--  funnels()

    --2nd layer of blocks
--  turtle.up()
--  perimeter()
--  layer2()

    --slab it up
--  turtle.up()
--  perimeter()
    slabs()

    --top it off
--  turtle.up()
--  roof()
end
run()